Population and the Environment

• Agricultural Productivity - The ratio of useful output (yield) to input, showing the efficiency of a farm.
• Commercial Farming - Agriculture with the intention of providing yields that can be sold commercially, making a profit.
• Cover Crop - A crop with a large surface area, used to cover a bare field to reduce soil erosion and maintain the structure of the topsoil.
• Arable Farming - Growing crops and plant-based foods.
• Crop Yield - The amount of grains, vegetables or fruits produced from a unit area of land (units = kilograms per hectare).
• Biologically Transmitted Disease - A disease that is passed on by a pathogen (e.g. a bacterium or virus), causing illness, e.g. malaria
• Demographic Transition Model - A model describing overall population change, mortality and fertility rates over time.
• Density - The number of people per unit area (often per km2 ).
• Desertification - Fertile land becomes dry and desert-like, reducing in productivity and vulnerable to erosion.
• Ecological Footprint - The amount of resources used in relation to the available resources on Earth. A footprint larger than 1 means consumption is greater than the available resources on Earth, making it unsustainable living.
• Epidemiological Transition Model - A model describing how morbidity varies - as a society develops over time, infectious diseases will decrease but non-communicable diseases will increase.
• Extensive Farming - Low inputs in relation to the amount of land farmed, i.e. low amounts of labour, capital investment or stock needed to produce a sufficient yield, but without too much investment.
• The Green Revolution - During the 1950s and 60s, more technology and efficient farming practices were adopted to improve crop yield.
• Gullies - Rills that grow in size over time into much larger ravines.
• Infectious Disease - A disease caused by pathogens (bacteria or virus) entering and multiplying within the body, e.g. flu, norovirus, Athlete’s foot.
• Irrigation - The process of regularly watering crops, rather than relying on precipitation for water.
• Malthusian Perspective - Population will increase exponentially, but resources available can only increase linearly. Hence, the population will eventually run out of resources (food, water, etc.)
• Morbidity - The occurrence of diseases within a population over time.
• Neolithic Revolution - A shift in mobile hunter-gatherer populations to agricultural communities approximately 12,000 years ago.
• Pastoral Farming - Tending to livestock and cattle-rearing to produce meat, poultry or dairy food products.
• Population Parameter - Different measurable factors to describe population: density, distribution, rate of change, etc.
• Population, Resources and Pollution Model (PRP) - A model that describes the positive and negative feedback loops between population, resources and pollution.
• Population - The number of people within a defined area.
• Rills - Small streams that develop over time as water erodes a small path on a slope.
• Riverbank Erosion - The degradation of riverbanks, causing large sections of the bank to erode and become waterlogged.
• Salinisation - An increase in the salt content of the soil, due to saline water rising within soils, poor drainage of irrigation water or groundwater levels rise.
• Sheet Erosion - The widespread removal of topsoil, washed away uniformly due to heavy rainfall and flooding.
• Simon’s Theory - Humans are the ultimate resource, and we will invent new ways to sustain life and resources.
• Structural Deterioration - The loss of the structure of the soil, especially pores within the soil that contain air.
• Subsidence Farming - Self-sufficient farming, where crops are grown only to support those growing the crops family or community, with little or no profit.
• Topsoil - The upper layer of soil, responsible for providing the majority of nutrients and structure for agricultural activities.
• Vector-borne Diseases (VBD) - Diseases that can be passed between individuals by parasites or through hosts, e.g. Chagas Disease, Malaria, Lyme Disease.
• Wind Erosion - High winds and dry climates transport soil particles and rocks across land, through creeping, saltation and suspension.
• Water Erosion - The degradation and wearing away of soil due to water.
• World Health Organisation (WHO) - A branch of the United Nations, aiming to improve global health and eradicate disease.